Method and apparatus relating to the production of metals



Aug. 14, 1923.

c. W. BALKE- METHOD AND APPARATUS RELATING TO THE PRODUCTION OF METALS Original Filed Feb. 10

@atentedlihng Ed,

oat eras earner cornice,

{ A BEIGE W. EALKE, GE HIZG'HLAND PARK, rnnmors, ASSIGNOE TO rnns'rnm NEW YGBK.

EEETHUD AND PTUQ RELATING} TQ THE PEQDUCTIONQT Application-filed February 10,1919, serial Ho. 276,1tl l. Renewed @otober 7, war. derlsl lilo. 563,148.

Toallwkomitmy am:

Be it known that l, (Immense W. BAIL-Kill, a citizen of the United States, residing at Highland Park, in the county ofliake and 5 State of Illinois, have invented a certain new and useful lmprovement in Methods and Apparatus Relating to the Production of Metals, of which the following is a lull, clear, concise, and exact description, refer- 16 once being had to the accompamying drawin forming a part oi this specification.

y invention is concerned with the methods and apparatus relating to the production of metals, and is especially con- 1 cerned with methods and apparatus used in the production of metals, and more specifically is concerned with the production of metals which readily oxidize at temperatures a proximating their melting points.

% l wi 1 describe my improved method and apparatus as used in connection with the reduction of misch metal, which is an aloy composed principally of cerium and certain other rare metals in combination with 2% a small percentage of iron. This metal can be most economically manufactured by the electrolysis of cerium chloride. Prior to my invention it has been the custom to electrolyze an impure chloride of this metal in cast iron pots or crucibles. lnj carrying out this process a graphite or carbon electrode is used as the anode of the furnace, and has its lower end projecting into the cast iron pot or crucible. The crucible acts as the cathode of the furnace. During the operation of a furnace of this t pc the misch metal collects in the bottom 0 the crucible and the fused salt floats on top of the misch metal, thereby excluding the atmosphere from the mlsch metal, and thus preventing its oxidation.

'After a furnace constructed in this manner has been operated for some .time,-it' is necessary to remove the inisch metal the crucible to prevent it from contactmg with the carbon or graphite electrode, and thus short-circuiting thef'source of electric current. By reason of the fact that the misch metal at the temperature at which it is formed in the furnace is highly inflammable, it'has'heretofore been the custom to. re-

move the cast iron crucible. with its content of misch metal covered by molten salt, and allow it to cool After the miseh metal has solidified and cooled below its ignition point, it Is necessary to break up the crucible In order to secure the misch metal. This method of removing the misch metal from the crucible is objectionable, first, by reason of the fact that it is expensive, as it entails the destruction of the crucible, and second,

because the misch metal whichis in contact with the salt is mixed with more or less or" the salt,

Another objection to this method of removing the misch metal from the crucible arises from the fact that it is desirable to operate a plurality of the furnaces in which the misch metal is made, and to connect these furnaces in series with a suitable source of current. ere it is necessary to bodily remove the crucible in order to remove the misch metal formed therein, the circuit sup plying the. current to the plurality of furnaces must first-be opened and held open until a new crucible can be substituted for the oneremoved, and tilled with the salt and started into operation. This requires time, and during this time the remaining crucibles are cooling ed more or less, and the operation of all of the furnaces is thus interfered with. llt hasbeen found desirable to keep the furnaces at a constant temperature, and this cannot be easily accomplished where it is necessary to remove the crucibles each time they are to be replaced by other crucibles,

The main objects of my invention are to provide a method and apparatus to overcome the above objections to the methods heretofore used in connection with the 0 eration of furnaces of the type described, rst, by providing a method and apparatusby means of which the misch metal can be removed from the crucibles without removing the crucibles; second,-by providing means forremoving the misch metal from each of a plurality of furnaces connected in series, without interrupting the flow of current through said furnaces. A further object of my invention is to provide a method and apparatus for removing the misch metal from the crucibles without ex osing it to the atmosphere, and thereby e iminating losses of the metal due to oxidization thereof. A still further object of my invention is to provide means for removing the misch metal lit till

ldlil being used for removing the misch metal.

from one of the furnaces;

Figure 2 is a side elevation of one of my improved furnaces and my improved apparatus for removing the misch metal there from;

Figure 3 is a view similar to Figure 2,-

except that my improved form of furnace is shown in longitudlnal section, and the vacuum pump is shown in transverse section;

Figure 4 is an enlarged detail view showing one-half of the mold removed from the other half;

Figure 5 is an enlarged sectional detail showing the means which I use to prevent molten metal being drawn into the vacuum pump; and

Figures 6 and 7 are a perspective view and a longitudinal section respectively of the end of the pipe which is used for withdrawin r the molten metal from the crucible.

imilar characters of reference refer to similar parts throughout the several views.'

Referring to Figure 1, wherein I have shown a plurality of furnaces comprising crucibles 10, preferably formed of cast iron, and co-acting electrodes '11, preferably formed of carbon or graphite, the reference characters 12 indicate terminal lugs formed integrally with the crucibles, which are used to make electrical connection with the cables 13 that connect the furnaces in series with each other. A shunt wound direct current generator G provides the necessary current for the furnaces. The reference character 14 indicates as a whole the means which I employ for removing the misch metal from the crucibles.

Referring to Figures 2 to 7 inclusive, this means will now be described in detail.

It will be noted from an inspection of Figures 2 and 3 that each furnace comprises a pier 15 formed of brick or other suitable material, upon which is mounted an enclosing casing 16 of sheet metal or other suitable material. This casing 16 receives the crucible 10 and is of suflicient :size to leave a space between the walls of the crucible and the casing. At one side, as shown in Figure 2, the casing 16 is provided with an opening, which may be closed by a sliding gate 17 that slides 1n the guides 18. I provide the construction just described for the following reasons: At the temperature at which furnaces of this type operate most efiiciently to produce the misch metal, the .misch metal is in a more or less plastic condition, and in order to render it sufiiciently fluid to be removedby the apparatus which I am about to describe, it is necessary to raise the temperature of the 'misch metal to its melting point. This might be accomplished by raising the anode 11 so as to increase the resistance between the anode and the cathode, and" thereby increase the energy consumed in the furnace, but I prefer to ac-' complish'this result without any material adjustment of the anode. During the normal operation of the furnace, the filling in the space between the wall of'the crucible and the casing is omitted, and the heat radiates rapidly from the crucible, thereby maintaining it at the proper temperature. When I wish to increase the temperatureof the misch metal to the melting point, I fill the space between the casing and the crucible with powdered mica or powdered silocel, which is a trade namefor a certain natural material having high heat insulating .properties. By this means I prevent the radiation of the heat from the crucible and the temperature thereof will eventually riseto the melting point of the misch metal.

The means which I employ for removing the molten misch metal from the crucible comprises a mold 18, which I preferably form in two parts, one of which is shown in side elevation in Figure 4. These two parts are bolted together by means of bolts 19,=and in order to make the mold air and li uid tight, I preferably insert a gasket Znot shown) of asbestos, between the two halves of the mold. The reference character 20 in, 105

dicates a source of suction, which I have conventionally illustrated in Figures 2 and 3 as being an air pump of the rotary type. This source of suction is connected with the mold by means of a-rubber hose 21, and suitable pipe sections 22, 23 and 24. The reference character 25 indicates a pipe section which is adapted to be inserted in the crucible and throu h which the molten misch metal is remove This pipe section is connected with the mold 18 by means of the ipe sections 26 and 27. The lower end of t e pipe section 25 is slotted as shown at 26 in these figures, to provide a plurality of tongues 27, the

lower ends of which rest upon the bottom of the crucible so that the misch metal can be drawn in through the slots 26. I preferably construct this pipe section of wrought iron,

and if it is not allowed to remain in the neeaeea the lower end of the pipe section 25 to pre vent any of the molten salt 28 from passing into the pipe section 25 when it 1s being introduced into the crucible. It will of course be understood that this plug will melt shortl after the insertion of the pipe 25, and t' us allow the molten misch metal to pass through the pipe section 25 and into the mold.

1 preferably connect the rubber hose 21 with the mold by means of several pipe sections, so that one of these sections, as, for instance, section 23, can be easily removed and replaced by another similar section. My

purpose in domg this is to provide means whereby the molten metal will be prevented from flowing into the rubber hose 21 and the vacuum pump when the mold becomes filled with molten metal. In order to accomplish this result if place a quantity of copper wire or shavings 29 or other material of good heat conductivity in the pipe section 23. With this arrangement, when the mold becomes filled with molten metal and a portion thereof passes into the ipe section 23, the heat is conducted away fi om the molten metal by means of the copper wire or shavings 29 so fast that the molten metal freezes and thus prevents any further progress of the molten metal into the pipe 23. After a mold is filled it is removed from. the pipe-section which connect it with the crucible and suction pump respectivel and another mold substituted therefor. t the same time the pipe section 23 is removed and another similar section filled with copper wire or other similar material substituted therefor. It is a comparatively easy matter to punch the small plug of copper mixed with misch metal from the pipe sections 23, and they can be umd over again for the same purpose. I have found that it is not absolutely necessary to provide the wires or shavings for conducting" the heat away from the misch metal, as the pipe sections 23 will usually cool the metal sulficiently to cause it to freeze, but more metal flows intothese pipes than when the wires or shavin s are used, and it is more difficult to isplace the plug of misch metal from the pipe sections when the wires are not used.

I shall now describe briefly the operation .of my improved apparatus and the method of removing the misch metal from the crucibles, although this operation will probably have been understood from the above de scription. When sufiicient misch metal has been formed in any of the crucibles, I fill the space between the crucible and the casing 16 with powdered mica or silocel 30, thereexcept at points immediately adjacent the plu 28, to a red heat, so as to prevent chilling of the misch metal by the insertion of the pipe 25.. The pipe 25 is then in serted into the crucible until its lower end rests on the bottom thereof, and the pump 20 is driven'by any suitable means to create a suction in the mold. The atmospheric pressure upon the molten salt in the crucible and the molten misch metal thereupon forces the molten misch metal through the ipe sections 25, 26 and 27 into the mold.

hen the mold becomes filled it is auto matically prevented from passing over into the pump by the means just described, and the mold is then removed and a new one substituted therefor. After sufficient metal has been removed from the crucible the operator raises the gate 17 and removes the powdered mica or silocel from between the crucible and the casing, thereby permitting the crucible to cool oh to the temperature at which it operates most eficiently. By means of the apparatus and method which l have 'ust described, the molten misch metal can e removed without destro ing the crucible, and without in any way afiecting the opera tion of the remaming furnaces. Furthermore, the misch metal is not exposed to atmosphere and is not oxidized. There is, of course, a slight amount of air in the mold l8 which will oxidize the first portion otmisch metal passing into the mold, but this amount is so small as to be entirely ne ligible.

while I have described my improved method and apparatus in connection with the production of misch metal, it is to be understood that they are capable of bein used in connection with the production 0' any metals which oxidize rapidl at temperatures approximating their me ting points, and consequently my invention is not to be limited to use in connection with misch metal. Furthermore, it should be understood that the word mold as used in the specification and the claims appended hereto is not intended to be limited to a device for receiving and molding the misch metal to a definite shape, but it is intended to cover any sort of a receptacle for receiving the molten metal from the crucible.

While I have described the details of the preferred embodiment of my invention, it is to be understood that it is capable of other adaptations and modifications within the scope of the appended claims.

at I claim is:

1. The combination with a furnace for producing metals, of a casing surroundin said-furnace, heat insulating means, an means whereby said casing can befilled with or emptied of said heat insulating means.

2. The method of electrolytically roducing an oxidizabl'e metal such as noise metal 1 which is in a more or less plastic condition v the electrolyzing current is passing there-- condition at the temperature at which it-is produced which comprises filling a plural-- at the temperature at which it is produced, which comprises filling a plurality of furnaces with the salt from which said metal is made, passing current through said furnaces in series, raising the temperature of said furnaces beyond that at which they normally operate, by preventing the radiation of heat therefrom, and withdrawing the metal from said furnaces out of contact with the atmosphere while through. i 3. The method of electrolytically producing a metal which is in a more or less plastic ity of furnaces with the salt from which said metal is made, passing current through said furnaces in series, raising the temperature of said furnaces beyond that at which they normally operate, by preventingthe radiation of heat therefrom, and withdrawing the metal from said furnaces, while the electrolyzing current is passing therethrough.

. 4. The method of electrolytically producing an oxidizable metalsuch as misch metal which isinamore or less plastic condition at the temperature at which, it is produced, which comprises filling a plurality of furnaces with the salt from which said metal is made, passing current through said furnaces in series, raising the temperature of said furnaces beyond that at which they normally operate, and withdrawing the metal from said furnaces out of contact with the atmosphere.

5. The method of electrolytically producfrom, and then withdrawing the molten metal from said furnace.

7. The method of removing metal from an electrolytic furnace in which the metal is'in a more or less plastic condition at the temperature at which the furnace normally operates, which comprises raising the temperature of said metal to the melting point and then withdrawing the molten metal from said furnace.

8. The combination with a closed mold, of

a source of suction, means for connecting said mold with said source of suction, comprising a conduit havin a removable section, a second conduit or connecting said mold with a source of molten metal, and copper shavings in said removable section for preventing the flow of molten metal into said source of suction when said mold becomes filled.

In witness whereof, I hereunto subscribe my name this 15 day of January, 1919.

I CLARENCE W. BALKE. Witness:

WALTER E. CARR. 

